Various forms of storage systems are used today. These forms include direct attached storage (DAS) network attached storage (NAS) systems, storage area networks (SANs), and others. Network storage systems are commonly used for a variety of purposes, such as providing multiple users with access to shared data, backing up data and others.
A storage system typically includes at least a computing system executing a storage operating system for storing and retrieving information on behalf of one or more client processing systems (may also be referred to as “clients”). The storage operating system stores and manages information in a set of mass storage devices.
Information stored at mass storage devices is typically replicated or “backed up” by a backup process that creates a backup copy of the information at a point in time. The backup copy may also be replicated or “cloned”. The cloned version of the backup copy typically shares data blocks with the replicated copy of a virtual block number (vbn) space maintained by the storage operating system to store the information. A data block in the vbn is typically mapped to a storage device block number in a storage device block number (dbn) space for storing information. The cloned version of a replicated copy is typically not used as an independent data object (for example, a database) because it may share data blocks with the replicated copy. Continuous efforts are being made to effectively use the cloned version as an independent data object.